Electronic musical instrument

ABSTRACT

In a keyboard electronic musical instrument having tone generators of frequency divider systems, every key is associated with and controls a plurality of tone keyers which respectively gate tone signals having frequencies being harmonically related with each other. The tone signal gated by one of the keyers is passed through a frequency shifter, while the tone signal gated by the rest of the keyers is not. Among the tone keyers, the above-mentioned one is a keyer for producing an attack signal, while the remainder are keyers for producing a normal lasting signal. Both signals, now being slightly out of harmonic relation, are mixed together and finally transduced into sound by a loudspeaker. The produced sound has subtly fine musical results with a sense of many different tone sources as in an individual-oscillator system instrument.

United States Patent 1 Uchiyama May 7, 1974 ELECTRONIC MUSICAL INSTRUMENT Primary Examiner-Richard B. Wilkinson Assistant ExaminerStanley J. Witkowski [75] Inventor. YaSllJl Uchiyama, Hamakita, Japan Attorney g or Firm-Holman & Stem [73] Assignee: Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu-shi, Japan [22] Filed: Aug. 21, 1972 [57] ABSTRACT In a keyboard electronic musical instrument havin [21] Appl' 282038 tone generators of frequency divider systems, ever? key is associated with and controls a plurality of tone [52] US. Cl 84/ 1.24, '84/1.25 84/l.26 keyers which respectively gate tone signals having fre- [51] Int. Cl. .1. GlOh 1/04 quencies being harmonically related with each other. [58] Field of Search 84/l.01, 1.1 l-l.l3, The tone signal gated by one of the keyers is passed 84/l.l91.26 through a frequency shifter, while the tone signal 1 gated by the rest of the keyers is not. Among the tone [56'] References Cited keyers, the above-mentioned one is'a keyer for pro-.

UNITE S ES PATENTS ducing an attack signal, while the remainder are key- 2,835,814 5/1958 I Dorf 84/].25 X ers for P l a normal lasting Both l 3,004'460 10/1961 Wayne 84/] 01 now being slightly out of harmonic relation, are mixed 3,007,361 11/1961 Wayne 84/l.0l together and finally transduced into Sound y a loud- 3,272,906 9/1966 De Vries et al. 84/].25 p a r- The p du d sound has subtly fine musical 3,288,907 11/1966 George .f. ..-84/1.25 results with a sense of many different tone sources as 3,493,668 2/1970 Bungerw 84/1.l3 in an individual--oscillator system instrument. 3,524,376 8/l970 Heytow 84/125 mKEYBOARD 3 Claims, 9 Drawing Figures TONE FILTER TONE L Half li an I GENERATORS 1 W i EA M FA TONE FREQUENCY FUER CIRCUIT KEYER SHlFTER IIIENTEI1IIIY T I9 4 3309.791

SHEET 1 0F 2 KEYBOARD K FIG. I PRIOR ART TONE KEYER SP 1 MIX F {ANIF TONE L MIXING FILTER GENERATORS E CIRCUIT CIRCUIT AMPLIFIER 2 TONE KEYER F G 2 mKEYBOARD I 1 TONE FILTER T KEYER CIRCUIT T\/ l R TONE L "Mwmj GENERATORS T F I TV TONE FREQUENCY FUERv F G. 3 KEYER SHIFTER CIRCUIT PHASE SH'FTER MODULATOR PS MI KHFF EXTREMELY FILTER CIRCUIT LOW FREQUENCY OSCILLATOR] MODULATOR LFO U2 LEVEL "IIIEIIIEDHAY 7 IQII 3.809.791

SHEET 2 BF 2 Fl 6. 5 KE BOARD FEQUENCY FILTER ----1 ;I ,sHIFTER (CIRCUIT TV I G I EN M F i =OUT TONE TV GENERATORS g,

QEA TONE FA KEYER FILTER cIRcUIT KEYBOARD Fl 6 6 TONE FILTER 8' F* KEYER CIRCUIT v 4'I OUT TONE I- TONE FREQUENCY GENERATORS I KEYER SHIFTER I EN4 LTTWI TV TONE EA (IMO I I FA I g FREQUENCY FILTER KEYER SHIFTER OIROUIT KEYBOARD- K I Fl 6. 7 n TONE I HKEYER 3 6 I EI MIX F AMP MIXINO IFILTER GElN l R k l'ORs I F ICIRCUIT CIRCUIT AMPL'F'ER I E2 I M FREQUENCY T'ONE I I I SHIFTER KEYER age Fl 8 SINGLE sIDE BAND BALANCE fI+fs DEMODULATOR MODULATOR f f fI+fs I (f8) BM BPF DM BAND-PASS FILTER H|GH FREQUENCY LOI L0 OSOILLATORUZ) HlGH f2=f +Af FREQUENCY OscILLATOR (f l I ELECTRONIC MUSICAL INSTRUMENT This is a continuation of application Ser. No. 115,646, filed Feb. l6, 1971, now abandoned.

BACKGROUND OF THE INVENTION 7 In most of the keyboard electronic musical instruments, every key causes a plurality of keyers to operate for respectively switching the tone signals having frequencies in a harmonic relation with each other, some for obtaining an attack effect, and some for combining partials into a complex voice. However, in case of the instruments with tone generators of frequency divider systems, the resultant effects are not very satisfactory. All the octavely related tone signals are locked together in frequency and phase. A conventional attack producing the same sound as that of a natural musical keyer which switches a tone signal with an envelope having an abrupt build-up to its peak amplitude upon depres'sion'of the associated key and a subsequent decay is provided in order to eliminate the monotony of a lasting organ tone keyed by a normal tone keyer, to increase a special performance effect, and to produce sounds which are very similar to sounds produced from a natural musical instrument. In general, the attack tone keyer switches a tone signal of an 8, 5 1/3, 4', 2 2/3', 2-or 1 3/5 foot register note, while the nor ma] tone keyer switches 8-foot register note. That is,

the attack signal has a frequency which is harmonically related with the normally keyed signal. However, in an electronic organ of a frequency divider system, those tone signals have their own fixed (locked) frequencies at all the times. In other words, the pitch (frequency) and the amplitude of the tone never fluctuate by the slightest amount at the beginning of the tone sounding as would be found in performance of the natural musical instrument. Therefore, it has been impossible for the conventional electronic musical instrument to eliminate such monotony.

Furthermore, as shown in FIG. 1, in the conventional keyboard electronic musical instrument, with square wave frequency divider tone generators, a fundamental frequency tone signal and a second harmonic tone signal are fed from square wave tone generators G to a mixing circuit MIX through tone keyers E and E respectively. These tone signals are mixed in the mixing circuitMIX, in such a manner that the level of the second harmonic signal is l/2'of that of the fundamental signal when the tone keyers E, and E are opened (conductive) in association with the operation of a corresponding key in the keyboard K thereby to obtain a stepped wave used to compensate for a disadvantage of the square wave tone generator system, namely, the shortage of even-harmonics. Further, this stepped wave is tone colored through a filter circuit F to a loudspeaker SP.

However, in such a conventional frequency divider system, phases and frequencies of the mixed evenharmonics signals arelocked with respect to the mixed fundamental signal. Therefore, the conventional electronic musical instrument has drawbacks that nothing but monotonous sounds is obtained and the sound produced is poor in natural sound sensation.

SUMMARY OF THE INVENTION instrument, by accompanying a deviation in frequency and a variation in amplitude at the beginning of a sound production. 7

A still further object of the present invention is to provide an electronic musical instrument, wherein a sound which is more intricate and richer in natural sound sensation than that produced by utilizing a conventional sound source, can be obtained in spite of utilization of a square wave sound source. 7

The foregoing objects and other objects as well as the characteristic features of the invention will become more apparent from the following detailed description and the appended claims when read in conjunction with the accompanying-drawings, in which like parts are designated by like reference symbols.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawings: FIG. 1 is a block diagram showing an example of the conventional keyboard electronic musical instruments,

FIG. 2 is a block diagram illustrating an embodiment of the keyboard electronic musical instrument according to the present invention,

FIG. 3 is a block diagram showing an example of the frequency shifter utilized in the present invention,

FIG. 4 is a graphic diagram showing envelopes of output signals furnished from a device shown in FIG. 2,

FIG. 5 is a block diagram of another'embodiment according to the present invention,

FIG. 6 is a block diagram illustrating a further embodiment of the present invention, I

FIG. 7.is a block diagram of a still further embodiment of thepresent invention,

FIG. 8 is a'block diagram showing an example of the frequency shifter shown in FIG. 7, and

FIG. 9 is a graphic diagram illustrating each of harmonic components and its level of an output signal of the device shown in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION 7 spectively controlled by a key in a keyboard K, a frequency shifter M which deviates (shifts) the frequency of an input signal slightly higher or lower, a tonecoloring filter circuit F for a signal from the normal tone keyer, a tone-coloring filter circuit F for a signal from the attack tone keyer, tone volume controlling devices'TV, and a resistor R which serves to directly introduce a signal of the attack tone keyer to the filter circuit F For. each .playing key of the keyboard, a plurality of tone keyers E and E would be provided in accordance with conventional-keyboard format, although carrier signal."

for purposes of this description, only a single tone" keyer pair coupled to a single key of the keyboard has been shown so as to preserve clarity. 1 I

In the above-mentioned frequency shifter M, a circuit of a single side-band'modulation system is employed, for instance, as shown in FIG. -3 wherein two modulating signals different, by 90 in phase are obtained' by letting an input tone signal pass through a 90- degree phase difference network PS Two extremely low frequency signals which are to be modulated (as carrier waves) and are different by 90? in phase are obtained from an extremely low frequency oscillator LFO. These modulating signals and carrier signals are respectively combined and amplitude-modulated in the modulator M1 and M2, respectively, thereby to obtain both side-band signals, and the thus obtained amplitude-modulated signals are mixed. Then, one side of each side-band signal is removed by the mixing andithe carrier component is removed by a high-pass filtercircuit l-IPF thereby to'obtain' a signal in which a frequency of the input tone signal is deviatedhighergor lower by as much as the extremely low'frequency of the Hereinafter, described'is the bodiment shown in FIGJZ.

Signals from the tone generators Gare introduced to the respective input sides of thenormal tone keyer E and the attack tone keyer E, by depressing the key'in the keyboardK. Atthis time, the tone signal from the normal tone keyer E appears at an output terminal OUT after having passed through the tone coloring filthrough both the tone coloring filter circuit F and the operation of the em-.

tone volume controlling device TV, and then is mixed with the signal from the normal tone keyer E Therefore, a sound obtained immediatelyafter the depres sion of the key contains mainly the signalfrom the attack tone keyer'E ,.and is resultantly different by as much as'the extremely low frequency from a frequency of a succeeding lasting'soun'd part. Thereafter the frequency (tone-pitch) of the mixed signal shifts gradually to that of'the lasting sound within increment of the level of a lasting sound. This is illustrated in FIG. 4, which comprises an envelope A of the lastingso und signal from the. normal tone keyer E andan envelope B with an abrupt build-up and a subsequent decay of an attack sound signal from the attack tone keyer E As is apparent from FIG. 4, a composition ratio of the two signals different in tone pitch is varied with time. Ac-

cordingly, a recognized tone pitch varys from a pointwhere a sound production starts till a point represented by reference symbol P, resulting in that the sound which is heard as if -it is vibrate-effected or frequencymodulated can be obtained. Thenafter a lasting sound of a regular pitch is heard.

Now, in this arrangement, if a frequency of the attack signal is slightly shifted higher, there can be obtained a tone pitch shifting effect as is found in building-up of. a sound-of a string musical instrument and the like. Furthermore the circuit may bedesigned so as to apply also an attack signal of the non-shifted tone pitch by connecting a circuit of the resistor R shown by a dotted line in FIG. 2.

- FIG. 5 shows acircuit in which the frequency shifter M is providedinanormal tone signal path. The-operation and effect of the circuit are relatively the same as those of: the case described above." Furthermore, frequency shifters whose'deviation frequencies are different from each other may be provided in both of the tone signal paths. I

FIG. 6 illustrates a circuit which is often utilized in thezcase of a square wave tone generators. In this cir-' ,cuit,'a.normal tone keyer E of a 4-foot tone signal is provided in addition to a tone keyer E of an 8-foot tone signal, and a frequency shifter Mn is. connected to the output side of the tone keyer-E thereby to deviate a frequency of the signal of the 4-footfregister. In this circuit, the signal of the 4 register is adapted to compensate for even-harmonics with respect to a fundamental wave of the fundamental tone signal of the 8' register, and the frequency shifter Mn servesto deviate a phase and a frequency of a signal of-the 4' register with respect .to the fundamental wave-thereby to increase, a naturalsound sensation. On the other hand, a frequency shifter Ma provided the output; side: of an attacktone keyer E,,- is adapted for slightly deviating a part of frequencies during the envelope of a combined output signal. The'operation and'effect of this circuit (attack signal path) are the same as those in theabovementioned case. I

-An electronic musical instrument of the embodiment shownin FIG. 7, according to the present invention, comprises squarewave tone generators G, tone keyers E1 (for the 8-foot signal) and E2 (the 4-foot signal) each of which is controlled by a key in the keyboard K,

' sideband" or a system obtaining a double side-band.

However, explained hereinis the systemto obtaina single side-band utilizinga modulator and a demodulator as illustrated in FIG. 8.

Asis shown in FIG. 8, the frequency shifter comprises a balanced modulator BM, a band pass filter BPF, a single side-band demodulator DM, a high frequency oscillator LO, whoseoscillating frequency is f,, and another high frequency oscillator L0 whose oscillating frequency is f,. The twice frequency or 4-foot signal (frequency f,) serves to balance-modulate a signal (frequency f e.g. 50 kI-I,) furnished from the oscillator L0, in the balanced modulator BM. Therefore, the output of the balanced modulator BM involves both sideband components consisting of frequences (f +'f,) and (f, f.) then, one of the two side band components, namely, (f f,) is eliminated out of the output by means of the band pass filter BPF, and the other of the two side-band components, namely, (f, f.) is fed to the demodulator DM. The demodulator DM demodulates the signal of the frequency component (f, f,)

with the reference frequency f,'- Af (where Af is an extremely low frequency, 0.5 to 10 Hz) furnished from the oscillator LQ, whose ocillatingfrequency isslightly is obtained as an output of the demodulator DM This t signal is a signal which is obtained by, deviating the frequency of the 4-foot signal lower by as much as Af. Thus, the 4-foot signal is slightly deviated, in frequency, and the thus deviated 4-foot signal is mixed with the 8-foot signal at a level of about 1/2 with respect to that of the 8-foot tone signal thereby to obtain a complex tone signal. Furthermore, the mixed complex tone signal may be formed by the following steps that, while the 4-foot signal being applied to the frequency shifter M, the 4-foot signal is also passed through a variable resistor VR as shown by a dotted line in FIG. 7, thereby to obtain a signal with no frequency deviation, and the latter signal is also mixed with the 8-foot tone signal. It is shown in FIG. 9, that all the harmonics, of the 4-foot signal, whose degrees (2, 6, 10,. are even-numbered times those (1, 3, 5, 7, 9, of the 8-foot signal are each deviated by as much as the frequency Af.

Herein before, a case where the 4-foot signal is frequency deviated by as much as the extremely low frequencyAf, has been described. However, in this case the fourth, the eighth and the twelfth harmonics are not present. Therefore, in case of forming a complex tone signal by mixing the 2-foot signal and the l-foot signal, if these footage signals are made to be mixed after having passed through the frequency shifters which serve to deviate the respective harmonics by Af in frequency, it will bring a more effective result. In addition, if the quantities of frequency deviation with respect to the harmonics are made to be a little different from each other, it will be much more effective.

The quantity of frequency deviation should be within a range from 0.5 Hz to 10 Hz for a fine result in operation, whichever the frequency is deviated higher or lower. When the quantity of frequency deviation is approximately within a range from 5 Hz to 7 Hz it produces an outstanding efiect in a musical performance. For a relatively quick tempo music, and within a range from 0.5 Hz to 2 Hz for a slow tempo music such as a church music.

While a few embodiments of the present invention have been illustrated and described in detail, it is particularly understood that the invention is not limited 1 thereto or thereby.

Iclaim:

1. An electronic musical instrument comprising, in combination, a tone generator means of a frequency divider system for providing a plurality of tone signals including harmonically related ones, a keyboard having playing keys, a plurality of controllable tone keyers provided for each respective playing key of said keyboard, said keyers being connected to said tone generator means and coupled to said respective playing key for control thereby, each said tone keyer respectively gating a tone signal from said tone generator means which has a frequency harmonically related with each other gated tone signal, at least one frequency shifter means receiving an output of a frequency f from one of said keyers and thereby transposing the frequency of the tone signal therefrom by a constant amount, a mixing circuit for mixing the output from said frequency shifter and the output from the rest of said keyers, and an electro-acoustic transducer for converting the mixed signal into sound.

2. An electronic musical instrument as defined in claiml, in which one of said tone keyers is an attack tone keyer for providing an envelope for the respective tone signal which has an abrupt build-up and a subsequent decay.

3. An electronic musical instrument according to claim 1 in which said tone generators are square wave signal generators and said plurality of tone keyers provided per key respectively switch to'ne signals having frequencies octavely related with each other. 

1. An electronic musical instrument comprising, in combination, a tone generator means of a frequency divider system for providing a plurality of tone signals including harmonically related ones, a keyboard having playing keys, a plurality of controllable tone keyers provided for each respective playing key of said keyboard, said keyers being connected to said tone generator means and coupled to said respective playing key for control thereby, each said tone keyer respectively gating a tone signal from said tone generator means which has a frequency harmonically related with each other gated tone signal, at least one frequency shifter means receiving an output of a frequency f from one of said keyers and thereby transposing the frequency of the tone signal therefrom by a constant amount, a mixing circuit for mixing the output from said frequency shifter and the output from the rest of said keyers, and an electro-acoustic transducer for converting the mixed signal into sound.
 2. An electronic musical instrument as defined in claim 1, in which one of said tone keyers is an attack tone keyer for providing an envelope for the respective tone signal which has an abrupt build-up and a subsequent decay.
 3. An electronic musical instrument according to claim 1 in which said tone generators are square wave signal generators and said plurality of tone keyers provided per key respectively switch tone signals having frequencies octavely related with each other. 